Hydraulic saw mill feed works



United States atent HYDRAULIC SAW MILL FEED WORKS Wiley T. Stockett, Jr., Mesa, Ariz., assigner to Gardner Machines, Inc., Richfield, Utah, a corporation of Utah Application April 30, 1953, Serial No. 352,088 3 Claims. (Cl. 60-97) This invention pertains to improvements in hydraulic saw mill feed works and is particularly directed to an improved hydraulic circuit and control mechanism.

One of the objects of this invention is to provide an improved hydraulic circuit for reciprocating a work carriage and manipulating Work gripping devices on such carriage.

Still another object of this invention is to provide an improved hydraulic control circuit for a saw mill feed works which is simple in construction and highly efficient and susceptible to precise and careful control by the sawer.

Still another object of this invention is to provide an improved hydraulic circuit and cylinder structure for reciprocating a saw mill carriage in feeding and return traverse motions.

it is also an object of this invention to provide in an apparatus as above recited, an improved supplemental control mechanism on the saw mill carriage for providing both high pressure and low pressure control functions for the set works and work gripping devices on the saw mill carriage.

Further features and advantages of this invention Will appear from a detailed description of the drawings in which:

The figure of the drawing represents a diagrammatic hydraulic circuit incorporating the features of this invennon.

For illustrative purposes applicant has shown his novel hydraulic control circuit applied to a saw mill feed works, but it is understood that this circuit is equally applicable to other similar mechanisms wherein a member is to be reciprocated under careful control relative to a tool or work piece to be operated upon by the machine'. The novel feed works and hydraulic system comprises a main reservoir 1 in which is kept a supply of hydraulic uidZ. A fluid pressure pump 3 receives its supply of iluid through the suction line 4, the pump being driven by a suitable motor 5. Discharge pressure from the pump 3 is delivered through the pressure line 6 and is connected through a line 7 to the main control valve 8a. The pressure line 6 is also connected through a `line 8 to the rod and pressure chamber 9 of a fluid pressure cylinder 10 which in turn has a piston 11 to which is rigidly fixed the piston rod 12. The piston rod 12 passes out through a suitable packing gland 13 and is connected by a suitable coupling 14 to the member 15 to be reciprocated, which for illustrative purposes may be a saw mill carriage mounted n suitable rollers 16 on guide tracks 17.

The control valve 8a may be of any type, but preferably of a design and characteristic of operation as shown in my co-pending application Serial No. 339,430 filed February 27, 1953, now abandoned. Such a valve has a control stem 1,8 which is sensitive to the operator in determining the pressure discharge from the valve 8a through a line 19 to the head end chamber 20 of the cylinder 10. Exhaust from the valve 8a may be conducted directly from the valve without packing glands being required to the reservoir 1 by placement of the valve Sa immediately above the uid level 2 in the reservoir 1 or suitable atmospheric discharge drain lines 21 may be utilized to' conduct the exhausted uid from the valve 8a back to the reservoir 1 as desired.

Thus, when the valve 8a is manipulated so as to apply the full pressure from the pressure supply line 6 to both the lines 8 and to lines 7 19, the dilferential in are`a subjected to the chambers 20 and 9 in the cylinder 10 will cause the piston 11 and its rod 12 to be reciprocated to the left as shown in the diagram. On the other hand, by connecting line 19 to drain line 21 lpressure in line 6 8 will return the piston 11 and rod 12 to the right as shown in the diagram. By intermittently adjusting the stem 1S of the valve 8a under careful operator control any degree of speed in either direction or feel can be obtained for the carriage 15 to determine the character of the cutting operation being undertaken.

It has long been a problem in reciprocating a carriage 1S auch as the saw mill carriage under discussion in this application, of connecting power to the carriage while it reciprocates back and forth without the necessity of utilizing hoses, flexible electric cables, or trolley wires to convey the energy to the carriage for any reciprocated position. In the present case all such apparatus has been eliminated and Huid pressure is supplied directly to the actuating mechanism of the set works and work grippers on the carriage. The arrangement comprises providing the piston rod 12 with a hollow passageway 22 which is in communication through a port 23 with the rod end pressure chamber 9 of the cylinder 10. On the outer end of the piston rod there is provided a port 24 connected through a suitable conduit 25 to the pipe 26 which is in turn connected through a check valve 27 to the high pressure accumulator 28. Discharge from the high pressure accumulator 28 is taken through the high pressure line 29 to the work gripper and set works control valve 30 for Huid actuable devices on the carriage from which conduits 31 are connected to the desired mechauisrns on the carriage 15.

Discharge from the valve 30 is connected through a line 32 to the lowpressure accumulator 33 which thereby maintains a minimum pressure in the line 32 and the connected line 34 which is in communication with the line 26 through the check valve-35. Thus, whenever the carriage is being reciprocated forwardly or being traversed back to starting positionk such as the movement of the carriage and piston 11 to the right in the diagram or when pressure is maintained in the chamber 9 for such purpose or for holding the carriage in retracted position, there is at the same 4time a uid pressure supply coming in through the line 26 into the accumulator 28 which is always available and kept charged in this manner for control by the valve 30 to manipulate the set works on the carriage 15 or other apparatus mounted thereon. It is also important to note that there are no moving flexible hoses which are bent back and forth during the operation nor are there any troughs, trolleys, or moving coils of wire required to apply the fluid pressure operation to the apparatus on the carriage 15. It is also to be further noted that the entire structure described is integrated in combination with the feed movement of the piston 11 in vthe cylinder 10.

While the apparatus herein disclosed and described constitutes a preferred form of the invention, it is also to be understood that the apparatus is capable of mechanical alteration without departing from the spirit of the invention and that such'mechanical arrangement and commercial adaptation as fall within the scope of the appended claims are intended to be included herein.

Having thus fully set forth and described this inven` tion what is claimed and desired to be obtained by United States Letters Patent is:

1. In a lluid pressure operating and control circuit for actuating a movable member, a reservoir, a supply of uid in said reservoir, a pump, a motor to drive said pump, a cylinder, a solid piston reciprocatable in said cylinder, a piston rod Xed to said solid piston extending outwardly from one end of said cylinder, a Variable control valve, a pressure line continuously connecting fluid pressure from said pump to said control valve and to therod end pressure chamber of said cylinder, a line connecting pressure discharge from said valve to the head end pressure chamber of said cylinder, an atmospheric discharge drain line from said control valve to said reservoir, a control stem in said control valve actuable to cause said valve to diierentially vary the relative pressure applied to said rod end pressure chamber and said head end pressure chamber of said cylinder, a hollow passageway in said piston rod, a port in said piston rod adjacent said piston connecting said hollow passageway directly into said rod end pressure chamber, and an outlet port in said piston rod located outside of said cylinder communicating with said hollow passageway, and uid pressure actuating devices mounted on said movable member connected to said outlet port of said piston rod.

2. ln a uid pressure operating and control circuit for actuating a movable member, a reservoir, a supply of fluid in said reservoir, a pump, a motor to drive said pump, a cylinder, a solid piston reciprocatable in said cylinder, a piston rod fixed to said solid piston extending outwardly from one end of said cylinder, a variable control valve, a pressure line continuously connecting uid pressure from said pump to said control valve and to the rod end pressure chamber o't said cylinder, a line connecting pressure discharge from said valve to the head end pressure chamber of said cylinder, an atmospheric discharge drain line from said control valve to said reservoir, a control stern in said control valve actuable to cause vsaid valve to differentially vary the relative pressure applied to said rod end pressure chamber and said head end pressure chamber of said cylinder, a hollow passageway in said piston rod, a port in said piston rod adjacent said piston connecting said hollow passageway directly into said rod end pressure chamber, and an outlet port in said piston rod located outside of said cylinder communieating with said hollow passageway connected to fluid pressure control devices mounted on said movable member, said movable member comprising a carriage, and a coupling between the outer end of said piston rod and said carriage, said uid pressure control devices including t a high pressure accumulator on said carriage connected lo said outlet port in said piston rod, a check valve be- `tween said high pressure accumulator and said outlet port to prevent back flow from said high pressure accumulator to said outlet port, a control valve on said carriage connected to said high pressure accumulator and to uid actuable devices on said carriage.

3, ln a iluid pressure operating and control circuit for actuating a movable member, a reservoir, a supply of liuid in said reservoir, a pump, a motor to drive said pump, a cylinder, a piston reciprocatable in said cylinder, a piston rod iixed to said piston extending outwardly from one end of said cylinder, a first control valve, a pressure line continuously connecting fluid pressure from said pump to said control valve and to the rod end pressure chamber of said cylinder, aline connecting pressure discharge from said valve to the head end pressure chamber ot' said cylinder, an atmospheric discharge drain line from said control valve to said reservoir, a control stern in said control Valve actuable to cause said valve to vary the relative pressure applied to said rod end pressure chamber and said head end pressure chamber of said cylinder, a hollow passageway in said piston rod, a port in said piston rod adjacent said piston connecting said hollow passageway into said rod end pressure chamber, and an outlet port in said piston rod located outside of said cylinder communicating with said hollow passageway connected to uid pressure control devices mounted on said movable member, said movable member comprising a carriage, and a coupling between the outer end of said piston rod and said carriage, said fluid pressure control devices including a high pressure accumulator on said carriage connected to said outlet port in said piston rod, a check valve between said high pressure accumulator and said outlet port to prevent back flow from said high pressure accumulator to said outlet port, a second control valve on said carriage connected to said high pressure accumulator and to fluid actuable devices on said carriage, a low pressure accumulator connected to the discharge from said second control valve and a second check valve connected between said low pressure accumulator and said outlet port to prevent back ilow from said outlet port in said piston rod to said second control valve and low pressure accumulator.

References Cited in the le of this patent UNITED STATES PATENTS 708,598 Thomas Sept. 9, 1902 872,038 Wilkin Nov. 26, 1907 1,822,690 De Leeuw Sept. 8, 1931 1,906,965 Hobson May 2, 1933 2,331,026 Harrington Oct. 5, 1943 2,572,385 Price Oct. 23, 1951 

